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Information Disclosure in Yokogawa FAST/TOOLS and CI Server Web Server

IdentifiersCVE-2026-11833CWE-200

CVE-2026-11833 is a high-severity information disclosure vulnerability affecting Yokogawa FAST/TOOLS and CI Server. According to the provided description, the vulnerable web server may return responses containing CI Server setting information. This results in unintended exposure of configuration data from CI Server through network-accessible web functionality. The affected products are FAST/TOOLS packages RVSVRN, UNSVRN, HMIWEB, FTEES, and HMIMOB in versions R9.01 through R10.04, and CI Server all-package versions R1.01 through R1.04. The disclosed setting information could be used by an attacker to facilitate subsequent attacks against the environment.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation exposes CI Server setting information to an unauthenticated remote attacker. While the provided content does not indicate direct code execution or privilege escalation, the leaked configuration data may reveal operational details useful for reconnaissance, targeting, follow-on exploitation, or chaining with other weaknesses. The primary security impact is loss of confidentiality, with secondary risk arising from the attacker using the disclosed information to support additional attacks against FAST/TOOLS, CI Server, or connected operational environments.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure of the affected web server interfaces by restricting network access to trusted management networks and authorized hosts only. Minimize external or unnecessary reachability to FAST/TOOLS and CI Server web services, and monitor for unexpected requests or responses that may expose CI Server setting information. However, specific vendor mitigation steps beyond updating are not provided in the available content.

Remediation

Patch, then assume compromise.

Update affected Yokogawa FAST/TOOLS and CI Server installations to vendor-provided patched versions. The provided content specifically states that the recommended remediation is to update FAST/TOOLS and CI Server to patched releases. Affected FAST/TOOLS packages are RVSVRN, UNSVRN, HMIWEB, FTEES, and HMIMOB in versions R9.01 through R10.04, and affected CI Server versions are R1.01 through R1.04.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

ACTIVITY FEED

Recent activity

6 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

6 SOURCESView more in app
What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.
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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity5

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES
MITRE CVE
cve.org · CVE-2026-11833
NVD
nvd.nist.gov/vuln/detail/CVE-2026-11833
MITRE CWE · CWE-200
cwe.mitre.org